The major objective of this proposed project is to obtain a better understanding of the health consequences of income fluctuations and the costs of variability in disease prevalence through a comprehensive examination of seasonality in rural areas of low-income countries. Longitudinal data from rural areas of four developing countries - Bangladesh, India, Pakistan and the Philippines - will be analyzed based on a dynamic economic model that incorporates production stages, biological relationships among consumption, work activities and health; health productivity effects; savings; uncertainty, and credit and labor market imperfections. Stages of crop production are allowed to differ in terms of the availability of food, the exposure to disease, the demand for labor, the resolution of uncertainty, the cost of credit and the extent to which health productivity effects are compensated in the labor market. The data sets provide nutrition intake, illness, activity and anthropometric measures collected at regular intervals over a period of 12 to 36 months. In addition, information is available on production inputs by production stage and outputs by crop-cycle, and on asset stocks and sales. The first component of the project entails a comprehensive comparative description of seasonality in each of the four countries with focus on seasonal fluctuations in cropping patterns, the availability of off-farm employment, prices and wages, illness, consumption and health among households in different wealth classes and among individuals differing by age and sex. The individual-level data on consumption, illness, and activities will then be used to estimate the proximate causes of observed fluctuations in labor productivity and in health and nutritional status. Agricultural production functions that incorporate health will also be estimated to assess the cost of health fluctuations. Tests of the ability of credit markets to enable smoothing of consumption and health and of discrepancies between on and off-farm labor productivity that arise due to smoothing problems will also be performed. The research project also examines the determinants of the seasonal allocation of resources and transfer mechanisms. This component will involve a combination of reduced form and structural estimation techniques in which approximations to production-stage decision rules and first-order conditions derived from the model are estimated.